Well, it depends what lenses you buy and how critical you are on the IQ. If you come from that Nikon, both will blow it away in IQ for sure. So you'll be happy regardless I think.

Olympus sensor is virtually identical to the NEX3F sensor BTW. So that is not it.

DOF...Well an APS-c has an advantage on DOF if we only look at the sensor. But bokeh is function of the lens. A shallow depth of field does not mean a good bokeh. It is how the lens renders the out of focus parts of the shot. You can be sure that you'll find a coiuple of really good Leica, Panasonic and Olympus lenses when it comes to bokeh. Not so much with the Sony unless you are okey with Manual focus lenses.

Also: DOF of course is also a function of the lens. Again: if you go for MF lenses the NEx has an advantage. If not, the Oly has quite a few fast lenses with good DOF for you like the 20 mm 1.7 Panny (I use it a lot on my EPL5), 45 mm f1.8 (excellent lens! and not too expensive). Well: look 'm up yourself. For the Sony you do not have lenses of that quality at that price that are similarly fast.

Actually, the Sony 50mm OSS is cheaper than the Oly 45mm and holds up in the optical department too. It's FOV may be slightly different (wider), it's light gathering abilities are greater (larger entrance pupil).